Inhibition of corneal neovascularization after alkali burn: comparison of different doses of bevacizumab in monotherapy or associated with dexamethasone

Background: To compare the effects of different doses of bevacizumab with both saline and dexamethasone on inflammatory angiogenesis in the rat cornea induced by small chemical lesions. Methods: Corneal chemical cauterization was performed on 24 rats. Animals were divided randomly into six groups and received a daily subconjunctival injection for 7 days of: balanced salt solution 0.1 mL or dexamethasone phosphate 4 mg/day or bevacizumab 2.5 mg/day, 3.75 mg/day, 5.0 mg/day or bevacizumab 5.0 mg/day + dexamethasone phosphate 4 mg/day. Clinical examination under slit lamp was performed daily for 7 days to evaluate corneal opacity and vessel size evolution. Computer-assisted quantitative image analysis was used to measure the total corneal area covered by neovascularization. Results: At final examination, the dexamethasone, bevacizumab 5.0 mg/day and dexamethasone + bevacizumab groups showed a significant lowering in corneal opacity score as compared with control (P = 0.024, P = 0.006 and P = 0.0113, respectively). Also, a significant reduction on new vessels size score was observed. Surface of corneal neovascularization was significantly reduced in dexamethasone, bevacizumab 5.0 mg/day and dexamethasone + bevacizumab groups compared with control (P = 0.045, P = 0.047 and P = 0.044, respectively). Conclusion: Our study demonstrates the ability of a 5.0 mg/day bevacizumab subconjunctival injection, in monotherapy or associated with dexamethasone, to cause a short-term involution of corneal neovascularization after corneal alkali burn. Combination of both of these treatments may have advantages to monotherapy approaches.